Attack on Homunculus
by ScarletRedfox
Summary: Creating a transmutation circle that Ed has no knowledge of it's purpose, he activates it and suddenly finds himself in an entirely different world than his own. In this world, it appears to be the end of the world, large humanoid monsters threatening the lives of the people living in walls. It seems humanity's greatest soldiers would have a handful with these alchemists...
1. Chapter 1

**_A/N:_** Alright! Well, this is my very first crossover and I think it's pretty obvious! ^^ I have to confess, I've taken a particular liking toward Levi and his battle prowess and the way he makes use of the **3DMG** (3D Moving Gear or alternatively _vertical maneuvering equipment)_. Got me freaking hooked!

Right, fangirling comes later, for now enjoy this little piece! ;)

 **WARNING:** I'll give a fair warning since this _is_ my very first crossover fic and I'm not sure if I've combined the elements of both universes all that well here. I may come back to it and edit it again though! Since this is Attack on Titan we're writing about, fair warning for mentions of blood and gore!

 **This crossover fic was a request originally from Bob (Guest), requesting a crossover between Fullmetal Alchemist and Attack on Titan!**

 **UPDATED: 19.07.2017!**

 ** _Disclaimer: I don't own any of these characters whether from Fullmetal Alchemist or from Attack on Titan, everything goes to their respective owners! I only own the plot and my OC (Lena)!_**

* * *

 **Attack on Homunculus**

"What exactly is this?" Roy scrutinized the strange looking transmutation circle, arms crossed skeptically.

Ed scratched his head, "...I'm not really sure..." Roy face palmed, "It was supposed to be a variation of Alkahestry with a bit of western alchemy..." he grinned uneasily, looking at the oddly written circles and symbols.

There was the distinct pentagram reminiscent of Alkahestry acting as the outer circle, a hexagram of Western alchemy was located within it and another far smaller pentagram was the innermost circle, every circle was connected and only one kunai blade was placed in the center of the whole transmutation circle.

Alphonse sighed, "Brother accidentally mistranslated a text we kindly received from the South and applied the formulas into the circle...however," he shook his head, "We aren't quite sure what it does,"

Roy rubbed his chin thoughtfully, looking back to look at Lena, "What do you think?"

She stared intently at the intricate symbols and markings, recognizing most but some others were completely unknown to her, "It's familiar for the most part, but I never saw some of the symbols before, I assume they are from the South?" Ed nodded in agreement, "Hm...no idea, maybe it could be the portal to hell or maybe it doesn't do a thing," she shrugged.

Roy smirked smugly, "Figures, not even two weeks after you've required your alchemy back you've already dived into strange satanic rituals, Fullmetal," his smirk grew larger when Ed was instantly in his face, waving his fist at him threateningly.

"It's not satanic you moron! It's perfectly normal alchemy!" he growled with a intense glare, "...for the most part," he finished off lamely, causing Al to sigh heavily.

Lena titled her head, stepping closer to the circle, "Well, why don't we try it?" she rubbed her hands together excitedly, before she was sharply pulled back by a strong hand on her shoulder, "Oof!"

"Hands to yourself woman," Greed spoke from behind her, his tall form towering over her by a head, a displeased frown on his face, "Don't make me remind you how you nearly set our house on fire," he hissed, still stingy about the fact she nearly destroyed one of his favorite coats.

She rolled her eyes, crossing her arms like a scolded child, "...Hey, I was learning flame alchemy and I may have overdid it a bit..." she glared right back, " And I apologized for your stupid coat didn't I? It's not even charred okay?!"

Greed wrapped his arm around Lena's head, pulling her head against his chest to gently rub his knuckles into her skull, "Oi, oi, my coat ain't stupid!" she playfully tried getting away, shooting half hearted insults at him that made Al scoot closer to Roy for protection.

Roy smirked, "Ah, young love..." he snickered at the bickering pair, thankfully they didn't hear him, Lena too busy trying to stick her fingers up Greed's nose.

Ed grinned, "So you finally admit you're old eh?" earning a burning glare from Roy.

"Well...I think it's safe to assume we shouldn't try using the transmutation circle since we don't know what it does," Alphonse deduced, already seeing the evil look his brother had.

A wrench hit him in the head just before Ed was about to say something stupid, "You are _not_ going to use that you hear me alchemy freak?!" Winry's voice boomed in the room and Greed winced sympathetically when Winry made a threatening motion to swing her wrench at him again.

Lena snorted softly, "I see marriage does wonders for you two," she grinned, discreetly fist bumping Greed.

Ed groaned, rubbing his head as he shakily stood up, "Yeah, it's doing wonders for my head every time one of her wrenches hit me," he scowled softly in the direction of his wife, "Where do you hide them all anyway?" he eyed her body curiously, earning a warning glare from her.

"That's for me to know and for you to question forever," she replied smartly, drawing her gaze back to the alchemical circle, "So, you drew a transmutation circle but you have no idea what it does?" she arched a pale eyebrow in question.

Lena supplied with a hand gesture, "Basically yeah, only problem is we can't just leave it," Winry shot her friend a confused look at that.

"...And why _not_?" Winry already suspected Lena was about to say something stu-

"Because I really, really wanna see what it does!" she jumped up and down excitedly, slapping Greed's forearm repeatedly in her excitement.

At Roy's confused and mildly disturbed gaze, he clarified blankly, as if been asked too many times already, "She gets violent when she's excited," Roy nodded at the simple explanation.

"No, I don't!" she slapped him one last time for good measure, prompting Greed to shoot her a _look_.

Ed cleared his throat, "Hey Al, where's Mei anyway?" maybe the little Xingese woman could help them solve this puzzle, "Or Ling for that matter?" looking around, the two were nowhere to be found.

Alphonse smiled nervously, "Uhm...Ling is raiding the fridge and I think Mei is helping him..." Ed's expression grew dark as he frantically ran out of his late father's old study.

"I _knew_ I shouldn't have let the little bastard outta my sight!" Ed's shout of outrage followed by Ling's pained yelp could be heard clearly from the kitchen.

Greed scratched his cheek, "Glad I'm not stuck in his body anymore, that would have been a pain in the ass," he scoffed and Lena smirked.

"Especially considering you two love different women, I wonder how that would have played out had doctor Marcoh not managed to separated you," Greed shivered violently at the thought of it, already picturing cursing and bloodshed.

Lena snickered, "Hm...I'm almost a bit disappointed...I would have loved seeing you and Ling bicker back and forth and try to take Lan Fan and I out on dates," she giggled, gently elbowing Greed's side.

The Homunculus had a evil grin on his face, "Oh yeah? What about sleeping next to each-other during the night?"

At that, Lena's giggles ceased and her expression grew horrified, nestling herself into Greed's arms to hug him tightly, "Don't ever leave me you stupid Homunculus!" her muffled cry into his shirt prompted Greed to laugh and gently caress her head, snickering at her reaction.

Clearing his throat, Ed returned, a beat up looking Ling in tow and a very apologetic Mei next to him, her head bowed.

Alphonse sighed softly, "Oh Mei..." he shook his head and patted her head, nearly falling over when her arms were suddenly around him.

"I'm sorry Alphonse! I just couldn't resist!" she cried into his shirt, comical tears spilling from her eyes in rapid succession as she hugged her significant other tighter.

Ed rolled his eyes, "I actually dragged you from your food raiding spree to see if you recognize this," he motioned toward the transmutation circle on the floor.

Ling and Mei turned serious, sobering up from the haze the smell and taste of food had put them in.

Ling's eyes narrowed, "Hm...I recognize most of the symbols but..." he turned to look down at the Xingese princess, "Do you...think what I do?" he rose an eyebrow and Mei's frown deepened.

The young woman rubbed her chin, "Yeah...it reminds me of it," at her friends confused gazes, Mei offered to explain, "Long ago, alkahestrists have tried employing different types of symbols into their Alkahestry, to try and create a new form of alchemy opposed to Western one and our own." She shared a look with Ed and sighed, "They succeeded, or at least in the sense that they created a new form of alchemy. In reality, when alkahestrists tried to activate the circle, many of them vanished. We tried analyzing the texts and formulas and try to find out what happened but the only conclusion we could take was that they have been sent somewhere else,"

Al's eyes widened, "Wait...you mean like time travel? But that's impossible!"

Greed couched into his hand, "...It was also impossible that the runt got his alchemy back but what do you know..." Ed fixed him with a grumpy look before concentrating back on Mei.

"No, nothing like time travel, more like being sent to a different world. A different world than the one we know, that place, if one believes the texts, aren't located anywhere within the world we know..." she watched the stunned expressions on her friends faces, "I don't know where we may be sent if we activate it,"

Ed hummed thoughtfully, "Is there a way to make it back?"

Mei frowned, "I'm not sure, since there have been no records prior to it..." she played with her fingers, uncertain.

"I'm in!" Ling suddenly shouted and surprisingly, it was Lena that shouted, _"What?"_

Ling looked at his surprised friends, "It's been a while since we've been on an adventure with our lives going the way they are. I think there is no harm done in going for a new adventure," he grinned, "Besides, maybe we can use alchemy at that other world and just teleport us back here,"

Winry frowned, "But what if you can't Ling? There's no telling where we will end up or if you're able to use alchemy to bring us back," blue eyes showed her insecurity, "What if we won't make it back?"

The group fell silent and Roy looked like he wanted to protest until Ed suddenly squeezed his arm firmly. The General looked at him questioningly, but the blond stayed silent.

Ed rose his hands placatingly in the air, "You know what, you're right Winry." He looked at the stunned blonde, "It's dangerous and we don't know if there's a way back for us," he sighed heavily, "I guess it's no use. We'll wipe it away then," he hung his head down, sighing heavily again.

Winry blinked, before slowly looking at her fiancé, "...Um...alright, you do that." She turned to look at Lena and Mei, "Care to join me? I still haven't cut that apple pie in the kitchen," she smiled secretly at her friends, who slowly nodded at her invitation.

"You behave," Lena waggled her finger in front of Greed's face before she reluctantly followed the women out of the old study and closing the door behind them.

"What in the world was that for-" Ling was promptly cut off at Ed's sudden jump.

Ed's slumped form immediately straightened and a all too evil, crazed look was in his eyes, Alphonse sighed and ran a hand down his face, "Oh no..."

"Huehuehuehue..." Ed rubbed his hands together, the same evil, disturbing grin on his face.

Greed deadpanned, "Is he on drugs?" he looked at Ling, who only shrugged and shook his head.

Ed looked at them with a grin, "Well? Whatcha waiting for? Better have a try before they come back!" Alphonse just managed to stop his brother from clasping his hands together by roughly tugging on his arm.

"Brother! What are you saying?! We can't just use it! We don't even know where it will teleport us to! Mei said it could be in a world where we won't be able to use our alchemy and then what?" he tried to reason with his sibling but he was too far gone.

"Come on Al, we will find a way back home, we always did before right?" Ed smirked.

Roy stared at the two brothers for several minutes, contemplating the very risky idea.

"Perhaps it's not such a bad idea," both brothers, including Greed and Ling, stared at him dumbly, "Just what Fullmetal said, we've dealt with riskier situations before and this is no different,"

Alphonse threw his hands in the air, "But General Mustang! This is a situation we can _choose_ to evade! We can willingly avoid trouble by not doing this!"

Ed chuckled, grinning, "Now where's the fun in that?" he winked, devil may care grin on his face when he turned to look at the two identical men, "Well? You guys in?"

Greed didn't even have to think about it before smirking, "You even need to ask?" he shot a look toward the door, "Hurry it up or something else than my head will be rolling if Lena finds out," he shuddered and punched Ling for the 'whipped' comment.

The men stood around the circle and Ed looked each of them in the eye, "Alright, let's do this!" sharing a look with his brother and Mustang, the two nodded and all three readied their hands in the trademark position.

A clasp of hands and the air charged with alchemical power, electric currents moving in and out of sight along the walls. The bright, nearly blinding blue light of the transmutation circle enveloped the whole group, blue turning to purple as the powerful currents washed over them.

* * *

They felt weightless for a moment, as if floating in midair, another bright, blinding light covered them and they covered their eyes, waiting to see what would happen.

The glowing stopped and they felt their feet hit solid ground beneath them.

When the group each opened their eyes, they all nearly screamed.

An impossibly large foot was coming down their way, the foot appeared human but there had been no humans who could possibly be as colossal as this! Quickly the group scrambled to get away, nearly stumbling over each-other as they scarcely dodged the massive foot that collided against the earth and created a foot-sized crater in its wake.

Smoke filled their noses and they noticed the chaos and fire around them.

"Everyone! Run!" a unfamiliar voice shouted from somewhere in the back and the sounds around them only registered now.

Screams of terror nearly made their ears ring, shouts for help sounded in between the loud noises of houses being destroyed and orders thrown about, to whom, they didn't know.

"What the hell?!" Greed shouted, watching how massive legs stepped over them and when the strange creature was just a few steps away from them in order to see it more clearly, Greed froze.

It looked like a human, or something humanoid anyway. It was hairless, save for the small tuft of hair on its massive head, it's movements seemed uncoordinated and slightly clumsy, but powerful as it stomped its way towards a large, stone wall, crushing houses beneath its wait without a care, almost as if crushing insects.

"After them! They aren't allowed to breach Maria again!" a blonde man dressed in military uniform shouted or at least, what the group assumed was a military uniform.

"You! The group there! What are you standing there for!? Clear out and head toward Wall Rose!" another man dressed in the same strange military-like uniform shouted at them.

"B-brother what...where are we?" Alphonse looked around, eyes widening in pity and horror at the death and destruction that surrounded them and the strange humanoid figures looming over the massive walls.

Ed growled, "I don't know Al, but I think it's best if we follow what that man said!" he looked over at his friends, "Come on! Follow those people!"

"Wait!" Roy shouted, glaring up at the creatures towering over them, "These...creatures, they're giving these people trouble, aren't they?" he readjusted his gloves, smirking, "Why not dispose of them?" he smirked and before Ed could say anything, Roy was already on the move, fingers snipping and the flames of death rushing toward their targets with pinpoint accuracy, engulfing their large bodies in painful heat.

To their amazement, it didn't seem to faze the beings too much, merely caused them to blindly swat away at the flames as if trying to hit annoying flies, wobbly carrying on their way.

"W-what?! They're immune to my fire?" Roy was promptly shoved out of the way by a blonde man dressed in military uniform.

"Get a move on! Fire doesn't work on them!" the man suddenly stopped, realizing Roy didn't have a weapon from which to produce the massive flames, "Wait, a second, where did that fire come from? How did you shoot it at them?"

Roy blinked, lifting his gloved hands, "With alchemy of course." He looked around himself, noticing all the soldiers exclusively employing weapons, "I'll explain later, how can we help?" Roy's question was met with a smirk.

"Let the Survey Corps handle this! You have to run towards Wall Rose!" the man nodded curtly south, "Since you're strangers here, follow the mob! And try not to get killed by the Titans!" he moved away from the odd group, running back towards his comrades and assisting in shooting off bullets at the creature's faces.

Wait...

"Titans?" Ling looked up, watching the massive humanoid creatures effortlessly bring down houses.

"You mean... _them_?" Al measly pointed up at the large humanoid monsters and yelled when one of them was staring straight at them.

It appeared to be far smaller than it's brothers, only towering about a foot or two above them. It's constant, eerie gaze unsettled the group and Roy moved into a fighting position, followed by Ed and Greed.

"Why is it staring at us like that?" Ed whispered, gaze locked onto the supposed "Titan" as the man had said earlier.

"I don't know but it looks...hungry?" Greed blanched when the 'Titan' suddenly sprinted towards them clumsily, limbs flailing about as if unused to using them, jaw wide open, exposing large square teeth, tongue flapping wildly in the air, salivating like dogs as they started to advance on the group.

Fire immediately filled its jaw and made it screech and stagger back, that gave Ed and Greed the opening they needed to launch a combined punch at its head, sending it crashing against the wall.

"What is this thing?!" Greed growled, looking at the advancing creatures in anger.

"Let's not stick around too long to find out," Roy motioned for the group to fell and they wasted no time in following the other screaming citizens, dodging falling debris and occasional massive feet from stomping them alive.

And then they saw it.

Wide, horror stricken eyes stared in disbelief and terror as one of the large creatures suddenly picked up a woman and mercilessly clamped its jaws around her midsection, biting down hard, the sickening crack of bone sounding as blood and organs spilled out of the gaping, dislocated mid section and onto the ground, the rest of the woman's body being rapidly devoured by the ugly creature.

"What the-" Ed clutched at his stomach, feeling physically ill at the display of the woman's intestines spilling from her dead body and the creature's jaws.

"Damn," Roy swore, looking away from the scene, equally holding a hand to his mouth. He may have seen his fair share of death and destruction in his time as a soldier, but not quite the brutality he witnessed here.

He had never seen a human being so mercilessly devoured before.

The incessant pushing of the crowd behind them forced the stricken group to move, running until their legs burned and breath was short, running until they saw another wall, this one appeared to be untouched yet.

Running towards a opening in the wall, the team advanced forward, nearly stumbling again when another one of those beasts squashed them under their weight and the screams of agony filled their ears behind them.

Why were they devouring humans? They looked humanoid themselves, were they cannibals? Why were they so deformed and large? Were these walls built to keep them out? Keep them from destroying these poor people?

Relief flooded the group when they squeezed themselves through the opening, taking a sharp turn to try and avoid the panicking crowd from running over them should they slow down.

"Mustang! What the hell is this?! Is this what the world looks like in a hundred years?! This is the end of the world!" Ed shouted hysterically, clutching at his heaving stomach from the grotesque scene he had witnessed earlier.

Ling panted heavily beside Greed, who rested an arm against a still standing house, looking visibly shaken by the recent events.

Roy slowly shook his head, collecting his thoughts, "No...I...I don't think so," he straightened up, watching how people ran in all directions to get away from the danger just behind the walls, "They appeared to not recognize alchemy..." his gaze hardened, "They're using artillery weapons here, I suspect that's their primary use of firearms. I doubt anyone here knows what alchemy even is," he stared down at his gloves, "But those... _monsters_ , those Titans...why didn't my fire affect them?" he frowned.

Ed slowly straightened as well, watching the terrified mob of people a few feet in front of them, "They did manage to stagger that smaller one though," he shivered, "They looked...deformed... they weren't even human..." his eyes widened, haunted, "They...they eat humans...they killed that woman..."

"But...why?" Alphonse's voice was quiet, his whole body shook, "Why did it bring us here? Is this what our future could look like? Maybe it's trying to warn us, that something worse than Father may threaten us in the future," his theory was met with silence and uneasy expressions until his brother spoke again.

The shake of his head already betrayed his answer, "No...Mei said it could only send us into a different world than our own...that means not even a parallel world...this isn't time travel, so it's...it's unlikely it would happen to us," his gaze shifted to the colossal walls behind him, "But... where are we then?"

The group looked at their surroundings and suddenly, they felt lost.

Lost in a world unknown to them, endangered to fall prey to the monsters the people here called _Titans_.

* * *

"Levi," the soldier with short blond hair and thick dark blond eyebrows glared sharply, staring down at the shorter male, "There have been reported sightings of a unusual group of strangers within our walls. They're now somewhere in Trost District,"

The shorter man's eyes narrowed, calmly setting his tea cup down, "Strangers? Are they survivors from Shiganshina when Maria was first breached?" recordings of all the survivors hadn't been fully able to be recollected, many people believed the number of survivors to be a bit higher than official stats.

Commander Erwin Smith shook his head, "Nobody recognizes them. A soldier from the Military Police reported seeing one of them release flames from their bare hands towards a incoming Titan," his face was set in a near to permanent scowl.

"...Flames from their bare hands?" he grunted, standing up from his sitting position, "Tea will have to wait then, I suppose," dark, cold eyes turned to his subordinate, "How many Titans are currently in Trost District?"

"Three," he nodded firmly, "I suggest you deal with this,"

There was a distinct metallic sound as blade slid out of its sheath, two sturdy swords in each hand as the man walked toward the door.

"Shall I call for Hange as assistance?" he rose a thick eyebrow, waiting for the short man's answer.

The door opened, shadows accentuating the muscled, shorter build of the Captain as the metal of his swords glinted in the harsh light, "I'll take care of this one myself, sir,"

The door slammed shut with a loud bang, the leftover tea in the warm cup shaking from the vibrations, the only movement in the now eerily cold room.

Something akin to a small earthquake shook the earth and Commander Smith found himself starting at the now spilled contents of the tea cup, watching his blurry reflection in them.

Moving toward the kettle near the fire, he watched the flames dance beneath the round metal, flickering hot colors of red and orange and yellow and his gaze narrowed.

The earth remained quiet.

* * *

Screams of terror cut through the air as human after human was devoured, torn out of their homes and mutilated by the large creatures called Titans.

A sudden large fist of stone crashed into a smaller Titan, who was about ready to tear off the other leg of a screaming man before dropping him at the harsh impact of the fist that sent him crashing into a rundown house.

Another clapping of hands and bindings materialized from the earth to wrap around the monster, pinning him down for the moment, when the Titan however tried to free itself, it succeeded, tearing through the feeble excuses for binds.

New ones materialized, these ones shining with a dark, metallic like gleam and when he tried to destroy them again, they didn't as much as budge, holding sturdy against the imposing power behind the large, naked hands of the Titan.

"Hey! We got him!" Ed shouted, grinning at the small victory that simple gesture brought them, "Good going Greed!" he shouted at his smirking friend, who dusted his hands off at his handy work.

"Gotta love carbon," he smirked, focusing in on a much larger Titan heading their way, "Hey! Ugly!" the Titan turned his head, away from a cowering family in their half destroyed home, to look at Greed, "Yeah you! Hell you're so ugly not even my blind, senseless and demented grandma would wanna touch you!"

Ling moved into a fighting stance, blanching at Greed's blatant verbal abuse, "Greed! We're supposed to take them down not taunt them!" he frowned.

Greed smirked, "How am I supposed to take them down when the bastard's not even heading my way?" he jumped from house to house, readying his fists when the deformed miniature head of the disturbingly large creature looked at him, "Eat that!" he punched it straight in the mouth, destroying a few teeth and tearing it's jaws open in the process as Greed used the hand that had wanted to swat away at him to his advantage to somersault of off it, landing safely on a rooftop.

Fire encircled the small Titan in the next moment, flesh melting away to reveal bones and in the midst of the burning, Greed noticed something horrifying.

The skin, the flesh, it was _healing_.

"Hey! Mustang! Turn off your fry fest for a moment!" Greed jumped off the roof and next to Ling again, running straight for Roy and Ed who stood dumbfounded at his shout.

"What is it?" Roy rose an irritated eyebrow, irked at being interrupted.

Greed's face was set in a scowl when he spoke, "These titans they're healing," three pairs of eyes widened, "They have regenerative abilities, just like us Homunculi." His gaze narrowed at the steam coming from the titan, "Maybe they are the same. Maybe they have a Stone in them that needs depleting," he cracked his knuckles, visibly itching for a fight.

Ed shook his head violently, "That doesn't make any sense! Why would they be so big? None of you were larger than a human, except Envy when he transformed into a green monster!" Ed's voice darkened at the last part, "You also didn't eat humans,"

Greed frowned, "Yeah, except Gluttony...Maybe in this world...these Homunculi are different," he looked at the struggling Titan, who kept snapping his jaws wildly in their direction, small feet kicking in the air.

"Look out!" Ling shouted when a hand nearly crushed him, landing a slash at the skin with his sword but the injury healed almost immediately, "Greed! I think I found your brother!"

This titan was far larger than the smaller ones they've fought until now, messy dark thin hair on top of its head, eyes a menacing violet as it stared down at the odd group at its feet.

Greed waved a fist at the unruly emperor, "You prick! Shut your mouth!" jumping from roof to roof again, Greed launched himself at the Titan's thigh, digging Ultimate Shield covered claws into its tough skin to scale his way up its body, barely dodging a massive hand that would have squished him if not for his fast reflexes.

The Homunculus jumped from its chest and in front of its face, fist connecting with its nose, breaking the sturdy, durable bone beneath it. Greed winced at the high pressure it put on his own arm, obviously their body structure wasn't that of a normal human. Their skin and bones were far tougher than any human's or Homunculi's Greed had encountered until now, that is, except his own.

Roaring when the beast managed to grab him with a colossal hand, its grip on Greed's struggling form tightened painfully, making Greed yell out in pain as his efforts to escape doubled the closer the Titan was moving him towards it wide opened jaw.

"Greed!" Ed shouted from far down under, Mustang all the while trying to burn the flesh of its legs to attempt to make the large Titan stumble or lose its footing, but it didn't budge an inch, instead opting to concentrate on eating Greed alive. Steam encircled the titans legs and thighs, burned and charred flesh healing and regenerating into the naked skin of the monster, not a single trace of injuries remained.

"Damn..." still struggling to at least free an arm and punch his way out, Greed froze when the blunt looking teeth of the Titan were now very close to him and Greed could smell the death and decay emanating from the monster's mouth, a pungent smell that made him want to wretch.

Another warning squeeze made several of Greed's ribs crack, causing him to lose his shield to quickly heal the damage.

Shit. Now he was without any real protection too.

Squeezing his eyes shut as the teeth grew closer, Greed felt the hot breath of the Titan against his upper body, the screams and shouts of his friends just barely registering to him until the Titan suddenly froze in the middle of clamping its jaws on him.

Opening his eyes in shock, Greed found the Titan's grip on his body loosening considerably, enough for Greed to slip out and finish healing before he delivered a strong, ultimate shield covered kick to its forehead, making the giant stumble.

A blur zipped past his field of vision and Greed tried to follow it with his gaze before he noticed he needed to get off the rapidly falling weight of the Titan, using its body to run across its torso towards a rundown house, jumping on the roof and sliding down the length before landing heavily on the ground, panting and trying to catch his breath and attempt to make his heart stop beating so wildly in his chest.

"Greed!" he turned his head to see the relieved expressions of Ed, Roy and Ling running towards him.

He grinned shakily, not trusting his legs to support his shell shocked weight quite yet, "Hey...guess I didn't end up as fodder for them yet,"

"You've gotten lucky," Roy commented with a displeased scowl, "Somebody...or something rescued you,"

Greed rose an eyebrow, "Rescued me?" he looked around, remembering the blur that had zipped past him. It looked like a bird or at least something that could fly judging from its high position somewhere at eye level with the Titan's neck area.

"And who are you, brats?" the deep voice cut through the atmosphere like a knife and when the friends turned to see who spoke, they saw a man there, murderous lust in his eyes, his dark bangs only further enhancing the shadows on his face as his cold gaze stared them down, two swords smeared with blood on either side of him, seemingly ringing with the screams of their foes defeat.

 **Part 2? ^^ I apologize for any OOCness concerning Levi, Erwin or any character in this crossover for that matter!**


	2. Of Soldiers and Alchemists

**_Of Soldiers and Alchemists_**

 _"_ _You've gotten lucky," Roy commented with a displeased scowl, "Somebody...or something rescued you,"_

 _Greed rose an eyebrow, "Rescued me?" he looked around, remembering the blur that had zipped past him. It looked like a bird or at least something that could fly judging from its high position somewhere at eye level with the Titan's neck area._

 _"_ _And who are you, brats?" the deep voice cut through the atmosphere like a knife and when the friends turned to see who spoke, they saw a man there, murderous lust in his eyes, his dark bangs only further enhancing the shadows on his face as his cold gaze stared them down, two swords smeared with blood on either side of him, seemingly ringing with the screams of their foes defeat._

" _Brats?_ Excuse me but who are you? And how old are you to be calling _me_ a _brat_?!" Roy fumed, gritting his teeth at the audacity of the young looking soldier before them, standing tall on the rubble.

Upon noticing just where exactly his gaze ended at his legs, Ed thought only one thing, _"...Damn, he's short!"_ his eyes widened, a familiar sense of anger welling up inside him until he realized that for once, that comment certainly wasn't aimed at him. Judging by the murderous expression on the man's face, he must have endured his fair share of shortie comments through his military career...for a very strange reason, Ed wanted to swap stories with him. Maybe they were on the same page about shortness...he looked young, so maybe he would grow taller more just like Ed had.

The male ignored Roy's questions, instead letting his gaze roam over each of them, his gaze narrowing, "What are you doing within our walls?" casually, he lifted his blade in front of him and the group readied for a fight...

Until he suddenly retrieved a white handkerchief from his pocket and started wiping away the blood from the length of his blade, attention shifted to meticulously clean his blades spotless.

...was he actually _cleaning_ his weapons? _Now?_

 _"_ _This guy is nuts!"_ Roy frowned, wondering why on earth a man that had looked ready to murder them a second ago was now casually cleaning his swords in front of the enemy?

Surprisingly, Ed voiced everyone's exact thoughts after getting over the mild shock when the bastard started cleaning his weapons, "Hey! What's the big idea?! You ain't gonna fight us?" the man's gaze was drawn to them again after pocketing his dirty handkerchief and wrapping it in another, cleaner one, and admittedly even Ed felt a bit... _apprehensive_ at the look in his eyes.

He remained quiet, flicking his wrist and straightening his blade parallel with the ground, the blade catching the dying sunlight and creating a even more sinister atmosphere with the way the man was looking at them, then at his sword, "Filth..." he muttered to himself and again shifted his attention to them, "I won't taint my blades with your filthy blood,"

"Filthy blood?" Ling frowned, "Now I'm offended..." he grabbed the hilt of his own sword, eyes narrowed, "He's not playing any games, he just took out that monster within the blink of an eye," he looked at the dead form of the titan near them, "Damn..."

Roy adjusted his gloves, "If you're not going to fight us, what are you planning to do with us?" his eyes narrowed suspiciously, ready to intervene should the soldier attempt anything funny.

The dark haired soldier smirked, "Imprison you, of course," and before any of them could brace themselves, pain flashed sharply through them before they fell to the hard, cobblestone ground.

Approaching feet were nearing Ed's fading line of sight, the voice of the man sounding commanding to some unseen soldiers lurking nearby, "Get them to the cell and send in for the Commander...he would want to see this,"

The booted feet stopped just before them, near Mustang's body, and he heard the sound of someone clicking their tongue loudly and saying, "Shit happens,"

Ed's vision darkened soon after that but not before thinking of one thing before his mind shut down, _"You were right, Winry..."_

* * *

"What the hell is this?! Get me out of here or I'll break your legs and beat you up with them baby dick! And you too forest for brows!" somewhere near him, Ed could hear the distinctive sound of Greed swearing and shouting and pounding on something metallic, a weary sigh coming from likely Mustang and his brother's whimper when Greed yelped in pain.

Slowly regaining consciousness and taking note of the dull ache somewhere at the back of his skull, Ed slowly rose from his laying position on what appeared to be a sorry excuse for a bed, looking straight at worried gold eyes identical to his own, "Are you okay, brother?" Al's soft voice soothed his headache and Ed attempted to smile, if not for his sake than for his brother's.

Carefully, he nodded, "I'm fine, Al." he looked around and noticed the dark, dimly lit cell they were kept prisoners in, surprisingly with no shackles attached to them, all except for Greed that is, "What...what happened?" he glared straight at the two men, one who he recognized as the short man that had threatened them.

Alphonse frowned, his voice quiet to not invoke the wrath of the two soldiers staring at them, "They surprised us and knocked us out, before they brought us here. I woke up not too long ago and the man that apprehended us was already here," he briefly looked at the bigger, blond man, "That man just came a few minutes ago. They talked, but we didn't hear what they said," he sighed.

Ed frowned, "So...why were we imprisoned? We didn't do anything wrong, did we? We helped defeat one of those titans, after all," Ed rubbed at the aching spot on his head, fixing his stare on the short angry man that had called them brats. _Hell_ , he had called _Mustang_ a brat, just how old was this guy?

The sternness in the shorter man's eyes never leaving once as he spoke to them, "I'll ask again, what business do you have in our city?" his gaze narrowed further, "The way you slew those Titans...I've never seen anything like that before," his gaze turned to Roy, "Flames cast from the palms of your hands...", his gaze shifted to Greed, "Managing to wound a Titan with your bare fists covered by a protective layer of skin...", he turned toward Ed and Al, "Manipulating the earth by clapping your hands and casting strange energy into it..." his voice hardened, "Who are you?"

Ed carefully thought of what to say and figured the best course of action was to simply tell the truth, "We are alchemists," the blond man's eyes widened, "We came here through alchemy but at the time we didn't know in what world we would end up in or if it would even work." Ed stared down into his hands, "Tell me..." he lifted his head to look straight at the shorter man, "What exactly are those 'titans'?"

The man scoffed, gaze unflinching and unchanging, "You killed one, didn't you? You may have guessed already that they aren't an easy opponent,"

The blond man cast a sidelong glance at his subordinate before deciding to answer the question, "They are large humanoid creatures, mindless beings hunting down humans to eat and kill," his slanted gaze swept over them, "There are, however, exceptions. Titans that actually posses some level of intelligence and awareness," he paused, seemingly collecting his thoughts before speaking again, "From what I've been hearing, you tell no lies of coming from a different world," he gave them all a once over, "Your clothes testify that as well," subconsciously, Ed stared down at his simple pants and shirt, mentally shrugging, considering they wore a sort of uniform he never saw before.

From what he gathered in their quick view of the town, it seemed rather simple, something akin to Resembool, but bigger, equipped with more houses and cottages. And...surrounded by massive walls.

"Those walls...I heard one of your men say those giants aren't allowed to breach 'Maria' again...is that one of your walls?" a fair eyebrow rose in question, resting his forearms on his knees.

The blond soldier spoke again evenly, "Yes, Maria is the outermost wall, followed by Rose and Sheena." He paused before speaking again, "They were built to withstand forces such as the titans, specifically, years ago. Humankind had already been almost completely wiped out before they decided to protect themselves by building the Walls." He looked directly at Ed, "Now, as mentioned before, you managed to kill a titan without the use of our equipment."

The shorter one cut in, "However, they would have been eaten had I not cut the titan's neck," there was no boasting in his tone or arrogance, simply stating the fact as it were.

Greed scoffed, crossing his arms, "Tch, yeah, I didn't need your help, shortstack," the soldier glared at him, "Besides, what's it gotta do that you cut its neck?" he tilted his head to the side curiously.

The blond one answered again, "Before we answer that, can we trust you to aid us in killing more titans? At least, until we figure out a way how to bring you back to your own world,"

Ed frowned and felt Alphonse gently nudging his side, leaning in to whisper to him quietly, "But brother, we know the transmutation circle, we can just leave if we want to. I want to help them, but I'm not sure if it's a good idea," Ed nodded slowly, catching Mustang's eye as he did so.

The dark eyes of his former superior told him wordlessly what his opinion on it was and Ed sighed. Staring at Ling and Greed, the xingese emperor looked distraught, frowning at their predicament and Greed seemed livid, looking ready to beat those two soldiers up to a pulp.

"We'll help you fight them off, at least until the situation clears a bit, but after that we need to get back home, got it?" Ed made sure his tone was firm and left no more room for discussion but it didn't faze the two at all.

The short one smirked, "Oh? Grown some balls have you, brat? Those titans invade our districts almost daily and many lives are lost because of it,"

Ed's face fell, "I'm sorry for what's happening to you, but please understand we can't stay here forever! We have families waiting for us back home!" the former Fullmetal alchemist was slightly startled when Greed's ultimate shield covered claws clanked loudly against the steel bars, arms straining as he glared daggers at the smaller soldier.

"Listen up _punk_ , this is all a sad and sappy story, but we got nothing to do with it. Like the runt said, we have wives and kids waiting for us back in our time so we can't stay here parading around and slaying those giants for you," Greed didn't flinch when the shorter male walked over to him, Greed towering over him by a good head but the soldier seemed indifferent by the height difference.

It looked like it would come down to a fight, but a sudden voice cut the tense atmosphere like a knife, "Captain Levi!"

The so called 'captain' broke his stare down with Greed to look at two people, equally dressed in uniforms, running towards them. One was a boy with messy brown hair and the other was a girl with a red scarf around her neck.

"What is it, brat?" Levi's voice made the youth flinch slightly before he collected himself.

"We heard you caught some outsiders-" he cut himself off before looking at all of them, stunned, "Is..is that them?"

Greed seemed to have enough, "Damn well it is pissant! We ain't a circus attraction, so stop staring at us like that," his growl was cut off by a very sharp sword pointing to his throat.

It was the girl. Faster than anyone could blink, she had drawn her sword and glared directly at Greed, her voice was low and threatening when she spoke, "Do not insult Eren," her gaze narrowed at him and Greed was about to say something until the blond man spoke up.

"Enough, everyone," he shared a look with Levi, "Levi, I want you to keep an eye on the prisoners for the time being. We'll release them tomorrow after we have come to an agreement," he looked at the 'Eren' kid and the girl, "Mikasa, Eren, you two head back to your barracks. It's past your curfew," he gave them a stern glare and the girl called Mikasa reluctantly withdrew her blade, all the while glaring at Greed as both she and Eren walked away from them with the blond guy.

Turning to look at Greed's face, the captain only said this, "Scum," Greed doubled his efforts to escape, trying to scratch at him with his claws but the man just moved away.

"Do you really think I'd let little shits like you escape so easily? These bars are reinforced," he stared at Greed specifically, "Not even your armor will be able to break it,"

Greed deactivated his shield, muttering something under his breath as he sat back down on one of the beds.

"Um...could we maybe get something to eat?" Ling raised a hand, looking sheepish but calm as he asked this.

Levi looked unimpressed, "Tomorrow, if the commander says so," he sat down, crossing his legs as he stared at them.

Roy decided to speak up after remaining silent for so long, "Would you mind formally introducing yourself? If it isn't too much to ask." He gestured to himself, "From where we come from, I'm the Führer and I worked in the State Military as a Colonel in the past, introducing yourself may not be bad," he waited patiently to see what the shorter male would answer.

His answer was blunt, "I don't give a shit where you worked or if you're the leader of the army. _Here_ , you're nothing but outsiders posing a threat to our people," his gaze spoke volumes as it darkened, "Now shut up and settle down, I don't want to have to straight you up,"

Roy frowned, sighing.

Turning toward Edward, he lowered his voice to a mere whisper, "There's nothing more to do than wait until tomorrow. Maybe that commander may help us, he seemed like the more...approachable one," glancing briefly in Levi's direction, Roy continued, "In any case, we have to find a way to draw a transmutation circle and get out of here as fast as we can,"

Ling suddenly cut in bluntly, "You're just scared your wife will beat you senseless after you agreed on something so reckless, right?"

Roy bristled, "N-no! Shut up!" he groaned in exasperation, burying his face in his hands.

Ed sighed long and hard, leaning against the wall behind him, frowning at Levi, who was watching them with a bored expression.

"Brother...he's scaring me," Al whispered and Ed could see how badly he wanted to go back home, he understood, he wanted it too...

"Yeah...seems like the scary type," he looked at Greed, who seemed to have settled down and was in some sort of glaring match with Levi, "Guess Greed isn't too fond of him either,"

"Damn...I wish we didn't draw that transmutation circle...Winry was right," he leaned his head back to rest against the wall with a dull thud.

Al smiled nervously, "Don't worry, we will find a way out," he smiled shakily at his elder brother, determined to cheer him up and lift his spirits.

Ed found himself smiling, despite their messy situation.

They may be chained and imprisoned here now, but once they were free, they could return back home. He almost relished the thought of Winry shouting his ears off once he got back.

 _Next Morning_

"I apologize for yesterday's...rude treatment towards you," he pointedly looked toward Levi, who was leaning casually against the wall, "However, we have no information concerning your abilities yet, much less if you're friend or foe,"

Roy stood up then, attempting to settle things once and for all, "With all due respect, sir, we beat a few of those Titans that plagued your city, it would be pointless to question our allegiance, would it not?" he gazed at the other man intently, watching his expressions.

"That may be so, but your abilities are dangerous and we have no knowledge of performing the same feats and manipulating objects such as you, surely you understand our people being wary of outsiders breaching our walls." He paused briefly, sending Levi a look, "However, we appreciate your efforts in helping us with the Titans. As such, I'm willing to negotiate a deal,"

Roy rose an eyebrow, "...And that deal includes?" he could see Edward tensing and he practically _felt_ Greed's increasing hostility towards Levi.

"You help us destroying the next wave of Titans swarming the city and in exchange you're allowed to go back to your own world," he crossed his arms, "Our scouts have found that some Titans were capable of intelligent thinking and we suspect some of them plan on releasing a big attack on the city any day now. We've lost many able men on our last expedition and it would be of great help if you would offer us your services to dispatch a majority of those Titans," he smiled slightly.

Roy's expression grew thoughtful, a small frown settling on his features as he mulled the deal over.

In truth, this deal benefited them more than it did him and his friends, but if it meant getting out of this world, they would need to accept.

"Now hold on a minute!" Edward suddenly sprang up, the chains keeping him from going any further than a step away from his bed, "We saw those giants eat humans, you said their numbers were great and some of them are larger than houses and buildings! It means me and my friends could get killed helping you out! That's not a very fair deal, _commander_ ," Ed crossed his arms, snorting defensively.

In a split second, Levi actually approached the steel bars and reached his hand out, grabbing Ed by the collar of his shirt and roughly slamming him against the bars, stretching the chains to their limits, Levi's glaring face bore into Ed's stunned one, "Now listen up you brats, we have you in our custody. If you won't accept the deal, there's a slim chance you'll ever get out of here." Levi's eyebrow rose when he felt incredible pressure on his wrist.

He looked down and followed the arm coated in the same layer of metal-like substance he saw on the battlefield and met furious violet irises, "Who're you calling brats, _shorty_? If you don't let him go I'll do more than just break your wrist," he gave a warning squeeze and Levi's hand moved to grab his blade when the stern voice of Commander Erwin penetrated the cell.

"Levi! Release him and step back!" Erwin's eyes flashed, "Now,"

Only hesitating but a moment, Levi slowly released Ed, causing the man to stumble and nearly fall if not for Greed steadying him.

The Homunculus glared daggers at the shorter male, crossing his arms, his shield slowly retreating.

Roy cleared his throat, "I'll only accept your deal under two conditions, commander," Erwin listened attentively, "The first one is, the captain won't harm my comrades for as long as we stay here and the second is, nobody is to prevent us from leaving this world once we deal with your Titan problem," he glared resolutely at the blond man, not willing to back down on his conditions.

Erwin sent a small but meaningful look at Levi, who 'tsked' silently and Erwin sighed, "Alright, accepted,"

Roy nodded, extending his hand through the bars as much as his chain would allow, "Good, we have a deal,"

Erwin nodded, shaking his hand firmly, "Release them!" the guard with the keys nervously looked at Levi, before nodding at Erwin and unlocking the cell door, unlocking each of their restraints.

Walking out of the cell one by one, Roy smiled at Erwin, "I'm glad we are on the same page,"

Erwin nodded, "So am I, however, before we require your help, you'll need basic training in order to understand how Titans work and how to effectively and quickly kill them on the battlefield." He looked down at Roy's gloves, "With your powers, I doubt you'd need to employ the use of our gear, however that will depend on how well you perform on the training grounds,"

Roy nodded seriously, understanding the circumstances.

Ed rubbed at his wrist, frowning at Levi, who only glared back. Greed growled lowly under his throat, Ling tried to calm him down by squeezing his shoulder, but the Homunculus was unrelenting in his glaring match with Levi.

"I believe this will make for a interesting time, Führer Mustang," Erwin nodded, smiling slightly.

Ed didn't know what exactly they've gotten themselves into, but he was willing to bet it wasn't anything good.

 **Put on hiatus until further notice due to too many projects I'm currently writing on! It may take a while for me to publish the next chapter. Thank you for reading!**


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